This invention relates to a lifting implement and more particularly to a lift adapted for installation in a van, pickup truck, or a bus for lifting cargo from ground level to the level of the floor or bed of the vehicle and vice versa so as to enable the cargo readily to be on-loaded and off-loaded from the vehicle. This invention specifically concerns itself with such a lifting implement for transportation of persons confined to wheelchairs.
The transportation of wheelchair patients has long posed a problem. When transported in a conventional automobile, the wheelchair patient is usually transferred from his wheelchair to the automobile seat. The wheelchair is folded up and stored in the trunk or placed behind the front seat. While some wheelchair patients can manage to get in and out of an automobile, by themselves, a substantial number of wheelchair patients require another person to assist them.
With the advent of passenger van vehicles, it is now possible for individuals and institutions to own a reasonably sized and reasonably priced vehicle which can transport one or more wheelchair patients while seated in their wheelchairs, thus eliminating the necessity of transferring the patient from his wheelchair to another seat. However, it is difficult to load and unload the patient in his wheelchair into and out of the van. Various ramps and mechanical lifts have been developed to facilitate loading and unloading of the wheelchair patient. Reference may be made to U.S. Pat. No. 3,874,527 in which a typical vehicle mounted ramp for wheelchair patients is disclosed. Among the known prior art lifts is a first type which utilizes a hydraulic cylinder which acts through a chain drive arrangement to move a platform on which a wheelchair is carried from ground level to the level of the floor of the van in a horizontal position. Another known lift utilizes a platform raised and lowered by means of cable and pulleys. A single winch shaft extends from side to side of this second lift below the level of the floor of the van. More particularly, this shaft is journalled in a well adjacent the doorsill in some makes of vans. Two separate cables are wrapped around this shaft so that upon rotation of the shaft, both cables are wound and unwound. With the first mentioned lift, an overhead structure is required within the van through which the wheelchair patient must pass upon entry or exit of the van. This overhead structure reduces the headroom of the van in the area of the door. With the second mentioned lift, the cables often tend to wind unevenly on the shaft and thus are wound at different speeds causing one side of the platform to move more rapidly than the other side. Also, upon raising the platform of the second mentioned lift to its vertical stowed position, continued rotation of the shaft often causes bending of the shaft which results in eccentric winding of the cables which in turn causes jerking of the platform as it is raised or lowered. Also, with the winch shaft of this second mentioned lift extending generally from side to side below the level of the floor, it can only be mounted in certain makes of vans having a well adjacent the doorsill and thus cannot readily be installed in other makes of vans.